Metal based Prussian blue composite materials with heterogeneous structures possess substantial potential for enhancing both ionic and charge transfer processes, ultimately expediting electrochemical reaction kinetics for various battery devices. However, the limited bonding between carbon materials and Prussian blue analogues (PBAs) and the uncontrolled nucleation rate of metal component resulted in limited specific capacity and cyclic stability. Herein, we introduced a novel approach for the in-situ synthesis of Ni-PBA with an inverted-pyramid structure on a three-dimensional ultra-thin carbon frames (3DUC) substrate via a hydrothermal method. The inverted pyramid structure fits tightly with the 3DUC during nucleation to form a one-piece stable structure. This integration effectively curbs aggregation and hasty nucleation tendencies of NiPBA. Furthermore, the abundant voids and interconnected networks within the 3DUC structure significantly reduce ion diffusion path lengths, thereby lowering the Na diffusion barrier and enhancing the material’s capacitance contribution rate. Consequently, this cathode material exhibits commendable initial capacity (125.2 mAh/g at 50 mA g−1) and exceptional long-term cycling stability (with a capacity retention of 89.06 % after 900 cycles at 50 mA g−1). These findings hold significant promise for advancing the commercial viability of metal-PBA based electrodes by rational heterogeneous structure design.

中文翻译：

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倒金字塔结构镍基普鲁士蓝与多孔 3D 碳作为高性能钠离子电池阴极的合理组合


具有异质结构的金属基普鲁士蓝复合材料在增强离子和电荷转移过程方面具有巨大潜力，最终加快各种电池器件的电化学反应动力学。然而，碳材料和普鲁士蓝类似物 （PBA） 之间的有限键合以及金属成分的成核速率不受控制，导致比容量和循环稳定性有限。在此，我们介绍了一种通过水热法在三维超薄碳框架 （3DUC） 衬底上原位合成具有倒金字塔结构的 Ni-PBA 的新方法。倒金字塔结构在成核过程中与 3DUC 紧密配合，形成一体式稳定结构。这种整合有效地抑制了 NiPBA 的聚集和仓促成核趋势。此外，3DUC 结构中丰富的空隙和互连网络显着缩短了离子扩散路径长度，从而降低了 Na 扩散势垒并提高了材料的电容贡献率。因此，这种正极材料表现出值得称道的初始容量（50 mA g-1 时为 125.2 mAh/g）和出色的长期循环稳定性（在 50 mA g-1 下循环 900 次后容量保持率为 89.06%）。这些发现为通过合理的异质结构设计提高基于金属 PBA 的电极的商业可行性具有重要前景。